Add efficient event parsing. #1264
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Currently, decoding events uses `aeson`. This works by converting the entire JS object structure into `Value`. This incurs significant allocation overhead. Events are high frequency and minimizing allocations is important. This PR introduces an `Event` parser (`Parser a`) that bypasses the conversion into `Value` by performing parsing in `JSM` directly on the raw `JSVal` (`FFI.Event` object). This works by replacing the `FromJSON` constraint in favor of the more efficient `FromJSVal` and parsing in an `ExceptT`, with two error cases. We expose a `FromJSON`-like interface for end users. The code stays the same, but - [x] Define and expose `withObject`, `(.:)` - [x] Adds `SyntheticEvent` nomenclature. - [x] Adds `executeDecoder` helper - [x] Adds various `FromJSVal` instances. This opens up the door for more aeson-combinators like `(.:?)`, `(.!=)`, etc.
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Make sure this is tested on the JS backend, w/ WASM it might be slower because it uses |
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Currently, decoding events uses
aeson. This works by converting the entire JS object structure intoValue. This incurs significant allocation overhead. Events are high frequency and minimizing allocations is important.This PR introduces an
Eventparser (Parser a) that bypasses the conversion intoValueby performing parsing inJSMdirectly on the rawJSVal(FFI.Eventobject).This works by replacing the
FromJSONconstraint in favor of the more efficientFromJSValand parsing in anExceptT, with two error cases.We expose a
FromJSON-like interface for end users. The code stays the same, butwithObject,(.:)SyntheticEventnomenclature.executeDecoderhelperFromJSValinstances.This opens up the door for more aeson-combinators like(.:?),(.!=), etc..:?,.!=added